Hello crøphyrus,
"I'm preparing for my next exam" This could be emphasising more the fact that you're studying for the exam, whereas "I'm getting prepared for my next exam" might place more of an emphasis on a psychological preparation. However both are essentially interchangeable.
"He was drunk" vs. "He got drunk" The first one describes his state only - he could have been drunk after only a glass of wine - but "he got drunk" could be that it was more intentional. Having said that, you could also say "He got drunk on only one glass of wine". I'm sorry that there isn't a greater difference between them! I would really need the context to advise you more fully.
Does "Get" change the meaning of "Drunk" & "Prepare"? Also, is IT "Be prepared" or "Be prepare"?
"Get" means that there is more of a process involved, either intentional or not. It is a verb of change.
The phrase you are looking for is "be prepared".
I do hope that helps.
Kind regards
Carolina